LCD display only showing black boxes.

Other Hardware Displays
1

I bought a LCD display and plugged it in this way:

Pin 1 to Arduino GND
Pin 2 to Arduino 5V
Pin 3 to Arduino pin 6
Pin 4 to Arduino pin 12
Pin 5 to Arduino GND
Pin 6 to Arduino pin 11
Pin 11 to Arduino pin 5
Pin 12 to Arduino pin 4
Pin 13 to Arduino pin 3
Pin 14 to Arduino pin 2

programming:

#include <LiquidCrystal.h>
LiquidCrystal lcddisplay(12, 11, 5, 4, 3, 2);
void setup() {
pinMode(6,OUTPUT);
analogWrite(6,15);
lcddisplay.begin(16, 2);
lcddisplay.print("Arduino");
}

void loop() {
lcddisplay.setCursor(0, 1);
lcddisplay.print(millis()/1000);
}

And when I run it there are only black boxes on the first row.

I have rechecked the soldering.
Please HELP!

2

Badly adjusted contrast? It might be helpful to provide exactly what model of LCD you bought and from where...

Regards,

Graham

3

The contrast voltage is normally set with a resistor rather than the pwm approach you are using.

If you don't have the traditional pot to set the contrast, you can use a fixed resistor from Vo to ground. Typically the value will be less than 2k but probably greater than 470 ohm.

If you indeed must use PWM, most tutorials I have seen use a fairly large capacitor 10-100 microfarad between the Vo pin and ground, and the pwm setting is more like 50 than 15.

4

Get your display running with a traditional pot to set the contrast and with a simple message generated in setup(). Preferably don't try to do anything in loop().

You can mess with variable contrast, which is hardly ever needed, later.

Don

5

It would be interesting to know from what site/ blog you obtained the instructions to do that?

it is somewhat helpful for us to know which sources are such a total disaster for the "newbies". "Instructables" seems to be a good source of bad information.

That you are getting the "blocks" indicates that the contrast is working to some extent, but using PWM to set it when a resistor is all that is required - and probably works better - is not a good idea. So for starters, you should sort out that matter. Try a 470 ohm resistor from pin 3 to ground.

Now the "blocks" indicate that you are in fact, not "talking" to the display controller, though it is possible that there is some interaction with the code.

Try wiring pin 3 of the LCD to ground with a 470 ohm resistor and running this version of the test code:

#include <LiquidCrystal.h>
LiquidCrystal lcddisplay(12, 11, 5, 4, 3, 2);
void setup() {
  lcddisplay.begin(16, 2);
  delay(100);  
  lcddisplay.print("Arduino");
  delay(3000);
}

void loop() {
  lcddisplay.setCursor(0, 1);
  lcddisplay.print(millis()/1000);
  delay(500);
}